Interaction between Ethanol and Stress on ACTH and β-Endorphin Secretion

The intraperitoneal infusion of ethanol (EtoH) (1 g/hr/kg body weight for 3 hr) to intact rats blunted the secretion of adrenocorticotropic hormone (ACTH) and β-endorphin induced by a subsequent 10-min exposure to mild, inescapable electroshocks (1.5 mA; 2 sec; four shocks/min) or by corticotropin-releasing factor (CRF). Conversely, administration of the shocks for 3 hr diminished the pituitary response to an acute i.p. injection of EtoH. While we have previously shown (Rivier C, Vale W Endocrinology 121:1320–1328, 1987) that prolonged stress induces a loss of pituitary responsiveness due to the depletion of pituitary ACTH stores, the infusion of EtoH did not cause statistically significant changes in pituitary ACTH content. In adrenalectomized rats, the infusion of EtoH caused an elevation of ACTH plasma levels that was significantly ( p ≤ 0.01) larger than intact animals. These rats also showed a blunted pituitary response to the acute injection of CRF, possibly because they were already secreting ACTH at a maximal rate. These results support the hypothesis that CRF, stress, and alcohol do not potentiate each other on pituitary ACTH and β-endorphin secretion.